Hi,
First, I would just point out you haven't had him very long and he's only a year old. It's a combination of learning the rules and he's just a crazy puppy, despite being a crazy puppy in an adult sized body.
My first question is whether you use a crate for Forest or if you have a place you confine him when you leave the house. If so, you can prevent him from coming to the door and "greeting" newcomers by putting him in his crate or behind the baby gate or whatever you use until the visitor has come in and Forest has had an opportunity to calm down some before letting him come out to meet them. When you let him come out, the visitor should IGNORE Forest, no petting, no talking to him, no looking at him until Forest has a chance to sniff and walk around them some.
Others teach and train the dog to go to their place, a bed or small rug, and have them lie down and Stay. This won't work on the first visit, you have to teach them in steps, 1) go to your place, 2) lie down, and 3) stay and practice it over and over, first without distractions, then with increasing distractions which could start low with you walking around while they're in a stay, one of the kids walking past, one of the kids running past, one of the kids and one of the kids friends walking past, etc. If he breaks his stay, you have to take him back to his place, put him back into a stay, and start over again. This is a slow, step by step process that will be useful for lots of things but it isn't as quick as putting the dog into a crate when a visitor comes over. If he learns this, when someone comes to the door, you tell him to go to his place and Stay, let the visitor come in, the visitor will ignore Forest as above, when Forest seems calm you let him up to wander around. The visitor should continue to ignore Forest until he's acting calm.
You can help them learn not to be so Cujo-like at the door, too. You need someone to help you practice this by being the "visitor" and coming up to the door and knocking or ringing the bell and practicing over and over. Like you've tried, you go to the door with "Cujo" on a leash. When the doorbell rings have him sit and start to open the door. As he lunges toward the door, which you haven't fully opened, you slam it in your dog's face and put him back into the sit. He wants to get out to say hello, jump, act idiotic and you have to keep him from getting what he wants. This also takes lots and lots of practice.
Our dog Lark is 4 years old now and she acts OK when others come over. We used the crate for her when others came over. As she got older she would calm down more quickly and could be released more quickly, especially if she already knew the person. With strangers or workmen, I still let her go into her crate and may or may not let her out- usually leaving her confined for workmen like a plumber or electrician. If it's a friend/visitor, I play that by ear.